This invention relates in general to conditional access systems and, more specifically, to detecting modifications to information within a content receiver.
Cable television (TV) providers distribute video streams to subscribers by way of conditional access (CA) systems. CA systems distribute video streams from a headend of the cable TV provider to a set top box associated with a subscriber. The headend includes hardware that receives the video streams and distributes them to the set top boxes within the CA system. Select set top boxes are allowed to decode certain video streams according to entitlement information sent by the cable TV provider to the set top box. In a similar way, other video program providers use satellite dishes to wirelessly distribute video content to set top boxes.
Video programs are broadcast to all set top boxes, but only a subset of those boxes are given access to specific video programs. For example, only those that have ordered a pay per view boxing match are allowed to view it even though every set top box may receive the match. Once a subscriber orders the pay per view program, an entitlement message is broadcast in encrypted form to all set top boxes. Only the particular set top box the entitlement message is intended for can decrypt it. Inside the decrypted entitlement message is a key that will decrypt the pay per view program. With that key, the set top box decrypts the pay per view program as it is received in real-time.
The set top boxes are located remotely from cable TV provider and are susceptible to hacking by pirates attempting to steal content. As those skilled in the art appreciate, set top boxes incorporate elaborate security mechanisms to thwart the efforts of pirates. However, these security mechanisms are occasionally circumvented by pirates who hack the set top boxes. Accordingly, methods for remotely detecting modification to the security mechanisms are desired.
According to the invention, disclosed are an apparatus and methods for detecting modifications to information within a content receiver. In one embodiment, a method for detecting modification to a content receiver within a conditional access system is disclosed. In this process, a content provider generates a message. The message is sent to the content receiver by way of a network. The content receiver gets the message from the network. The content provider detects any unauthorized modification to the content receiver.
In another embodiment, a process for detecting modification to a content receiver within a conditional access system is disclosed. In one portion of the process, a content provider generates a message that intentionally includes an error. The message is sent to a content receiver by way of a network. At some point, the content receiver accepts the message from the network. An exception condition is recorded if the content receiver fails to notify the content provider of the error in the message.
In yet another embodiment, a method for detecting modification to a content receiver within a conditional access system is described. As part of this process, a content provider generates a message. The message is sent to a content receiver by way of a network. At some point, the content receiver accepts the message from the network. Detecting failure of the content receiver to check at least one of authentication of the message and authorization of the message.